This aims to compare the safety, efficacy and cost benefit of enoxaparin administered once or twice daily subcutaneously to intravenous continuous-infusion heparin therapy in the treatment of lower extremity deep vein thrombosis and pulmonary embolism. Efficacy will be measured by the incidence of recurrence of any documented venous thromboembolism in all treated patients completing the study. Socioeconomic measurement will be the total health care costs.